Inhibit error messages for unused static functions?

Question

In C code, if a function is used exclusively within a file, it's good practice to declare it to be static.

But sometimes I define a function to be static but don't actually use it (yet), in which case the compiler complains at me:

../src/app.c:79:12: error: 'foo' defined but not used [-Werror=unused-function]

What's the right way to tell the compiler (gcc in this case) that unused static functions are okay?

score 6 · Accepted Answer · answered Jun 07 '22 at 21:16

6

You can add the unused attribute to the function:

__attribute__((unused))
static void foo(void)
{
}

answered Jun 07 '22 at 21:16

dbush

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This answer has the advantage that you apply it to specific functions rather than a global compiler switch. – fearless_fool Jun 07 '22 at 22:20
Nice. This works for variables too, I believe. – Paul Sanders Jun 07 '22 at 23:50

score 1 · Answer 2 · answered Jun 07 '22 at 21:18

1

You can disable that specific error by providing this argument to GCC:

-Wno-unused-function

The error itself contained a hint that you could do this.

answered Jun 07 '22 at 21:18

David Grayson

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score 0 · Answer 3 · answered Jun 07 '22 at 23:51

0

I am lazy and standard compliant, and just do inline, and it suppresses the warning.

static inline void foo(void)
{
}

answered Jun 07 '22 at 23:51

KamilCuk

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Ooh - that's cool. I would not predict that `inline` would have that effect. – fearless_fool Jun 08 '22 at 00:16

score 0 · Answer 4 · answered Jul 18 '23 at 08:46

0

Somewhere in a function: (void)unusedFunctionName; This is how you can suppress unused variables warning for any variables and it is compiler independent (some compiler may still warn, but most probably don't and it doesn't break code for other compilers).

answered Jul 18 '23 at 08:46

12431234123412341234123

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All true, but the question is about suppressing warning for unused static functions, not unused variables. – fearless_fool Jul 18 '23 at 15:56

Inhibit error messages for unused static functions?

4 Answers4

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